A fuel cell (for example, polymer electrolyte fuel cell) is a device in which a fuel gas containing hydrogen and an oxidant gas containing oxygen, such as air, are electrochemically reacted with each other so as to simultaneously generate power, heat, and water.
The fuel cell generally has a structure in which a plurality of cells are laminated, and these cells are pressurized and fastened by a fastening member such as a bolt or a band. Each cell is constituted by sandwiching a membrane-electrode-assembly (hereinafter, referred to as an MEA) by a pair of plate-shaped conductive separators.
The MEA includes a polymer electrolyte membrane, and a pair of electrode layers disposed on both surfaces of the polymer electrolyte membrane. One of the pair of electrode layers serves as an anode electrode, whereas the other thereof serves as a cathode electrode. Each of the paired electrode layers includes catalyst layers mainly containing carbon powder on which a metal catalyst is supported, and a gas diffusion layer that is a porous conductive layer to be disposed on the catalyst layers.
The fuel cell generally has a structure so that an electrochemical reaction is developed to generate electrical power and heat, when a fuel gas and an oxidant gas are respectively brought into contact with the anode electrode and the cathode electrode through reactive gas passage groove (fuel gas passage groove or oxidant gas passage groove) provided in the pair of separators.
In this field of fuel cells, various proposals have been made conventionally in order to achieve further higher power generation performance. As one of the proposals, there is a technique disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2007-157578). This Patent Document 1 discloses a reactive gas passage groove containing a first reactive gas passage provided in a gas diffusion layer and a second reactive gas passage groove provided in a separator. More specifically, the technique in Patent Document 1 is intended to provide not only the separator but also the gas diffusion layer with the reactive gas passage grooves, and combine the reactive gas passage grooves to configure a large-area reactive gas passage groove. According to this technique in Patent Document 1, the sufficiently large cross-sectional area of the reactive gas passage can be ensured to improve the power generation performance, and the volume of the separator molded can be reduced to improve the productivity of the separator.